In the United States and many foreign countries, ski areas utilize snow making apparatus to supplement natural snow fall. Even in high altitude locations with normally high precipitation rates, ski area operators rely on regular snow making to maintain trails and slopes in good condition after the wear and tear of heavy ski activity. In areas further south, with lower altitudes, snow making apparatus means the difference between staying open all winter and shutting down for part of the season. Thus, snow making is a vital part of almost all ski area operations.
Heretofore, snow making methods and apparatus have generally been classified as "air/water" and "airless" types. The prior art "air/water" type snow making apparatus required compressed or pressurized air at relatively high air pressures of up to 100 PSIG or more. So-called "airless" types of snow making apparatus do not use compressed air but used fans to disburse water droplets into the air instead. Such devices are shown for example in U.S. Pat. Nos. 2,676,471 and 2,968,164.
While such devices have been used for many years, they have been found to suffer from a variety of inadequacies. Generally the airless type devices operate well at lower temperatures of less than 24.degree. F. while the high pressure "air/water" type devices operate well only up to 28.degree. F. In addition, the high pressure "air/water" devices are disadvantageous because of the relatively high air pressures needed for their operations.
In order to overcome these deficiencies, an improved snow making apparatus and process was developed as disclosed in U.S. Pat. No. 4,916,911. In accordance with the method and apparatus disclosed in that patent, improved snow making was achieved by a process which provides a stream of pressurized air at low pressure in the general range of 30 psi, a stream of pressurized water, and which combines the air and water streams to produce a mixture of air and water. The snow making apparatus or gun illustrated in the drawings of that patent includes an initial aspiration of air to form a stream of air and water, and then that stream is mixed with ambient air to form a second stream that is disbursed into the atmosphere. In addition, the apparatus of U.S. Pat. No. 4,916,911 uses a nucleating agent to promote freezing of the water in the discharged mixture stream at the discharge end of the apparatus.
The snow making apparatus disclosed in U.S. Pat. No. 4,916,911 has numerous advantages, the principal of which is the ability to produce high volumes of high quality snow at relatively low air pressures of 30 psig. However, the construction of the apparatus illustrated in that patent is relatively complex, with multiple parts. It is important in the operation of that device that the various components be maintained in axial alignment, because the velocity of the air and water passing through the apparatus approaches sonic speeds. However, the complexity of these devices construction makes such alignment difficult to achieve and then maintain. Moreover, the construction of the snow making apparatus disclosed in that patent makes assembly and disassembly for repair purposes difficult.
Another problem with existing snow guns of all types is that they will not make snow spontaneously in most conditions. To solve this problem a so-called nucleator is usually added to the snow gun, as is done in the apparatus of U.S. Pat. No. 4,916,911. The nucleator is, in effect, a miniature air/water gun which operates at an extremely high air to water ratio. It produces ice crystals at temperature up to 32.degree. F. which are directed into the plume from the airless or air/water gun. This has a catalyzing effect which triggers the plume into making snow. This effect is due to the temperature well below freezing but ice will not form until a single ice crystal has been introduced. The use of necleators introduces an additional expense and complexity to snow making.
According, it is an object of the present invention to provide an improved snow making apparatus which is highly efficient over a wide range of temperatures, particularly at relatively high snow making temperatures.
Another object of the present invention is to provide a snow making apparatus which will produce improved quality and quantities of snow, yet which is relatively lightweight in construction and easy to assemble and dissemble.
Another object of the present invention is to provide a snow making apparatus which is simple to construct and has substantially zero leakage of air or water.
Yet another object of the present invention is to provide a construction for a snow making apparatus which insures concentricity of the components thereof that contain the high speed and relatively high pressure air and water during the snow making process.